The study notes that triclosan is classified as an endocrine-disrupting compound (EDC), which are believed to negatively impact human health by mimicking or affecting hormones. The researchers hypothesized that with exposure to triclosan, a young individuals' immune systems may not fully develop due to the ability of the compound to limit exposure to specific microorganisms.

The researchers reference the “hygiene hypothesis,” which argues that the developing human immune system needs exposure to microorganisms for proper stimulation of T helper cells, TH-1 and TH-2 cells. Conversely, most individuals with allergies have an imbalance in TH-1 and TH-2 cells, with more TH-2 cells that promote antibody production. The researchers postulate that during the development of the immune system, triclosan may modify immunologic responses to micro-organisms in such a way that imbalances between TH-1 and TH-2 cells are created. These T-cell imbalances may stimulate autoimmune reactions and allergies.

The researchers plan to further assess the long-term effects of triclosan in individuals to determine whether a causal relationship can be established.